Conciseness

The body is dense and project-specific — checklists, a file table, concrete failure signatures — with almost no explanation of concepts Claude already knows. However, the 'Guardrails' section largely restates checklist items ('Do not ship a fix in one adapter without verifying the sibling', 'Do not verify env changes with probes only' repeat sections 1 and 6), which is minor padding that could be trimmed. It sits between the level 5 'every token earns its place' anchor and level 4 'minor instances of over-explanation', closer to 4 due to this repetition.

Actionability

Guidance is fully executable for an instruction-only skill: exact file paths ('electron/main/ipc/schemas.ts', 'src/lib/providers/schemas.ts'), a concrete command ('bun run typecheck'), specific grep targets, exact failure output ('env: node: No such file or directory'), and precise verification surfaces (GUI launch, Settings → Providers). Matches the 'copy-paste ready ... specific examples cover the common cases' anchor; level 4's 'minor gaps' does not fit.

Workflow Clarity

The process is clearly sequenced: a seven-section symmetry checklist ordered by concern, followed by a verification section with explicit validation steps (typecheck always, real turns with each provider, GUI launch for env changes, probe-surface check for tooling-status changes) and a required output report. This matches the 'clear sequence with explicit validation steps; checklists for complex processes' anchor and exceeds level 4.

Progressive Disclosure

No bundle files exist (references/, scripts/, assets/ are absent), so the ~130-line body must stand alone; it is well organized with clear section headers, a file table, and inline pointers to repo docs ('docs/developer/adding-a-provider.md', 'docs/providers/codex-upgrade-checklist.md'). This is 'good structure; most content appropriately placed' (level 4) rather than 5: at this length, sections like 'SDK upgrade hygiene' and 'Common Failure Modes' could be split into reference files to slim the always-loaded body, and the doc pointers are inline code paths rather than clearly-signaled references.

Specificity

Concrete actions and coverage are explicit: 'Keep Stave's Claude and Codex provider runtimes in sync when editing one of them', 'executable lookup, env construction, CLI session launch env, tooling status probes, or any provider-agnostic behavior', plus exact file paths. Matches the 'multiple specific concrete actions; comprehensive coverage' anchor; nothing above it exists, and it is well beyond the 'several specific actions; minor gaps' level 4 anchor.

Completeness

Both what ('Keep Stave's Claude and Codex provider runtimes in sync when editing one of them') and when ('Use when a change touches ... Trigger on phrases like ...') are explicit with concrete trigger phrases, exactly matching the level 5 anchor. It clearly exceeds level 4, where the 'when' is present but less explicit.

Trigger Term Quality

Trigger coverage is comprehensive with synonyms and exact identifiers users would naturally say: 'provider runtime', 'claude adapter', 'codex adapter', 'sibling adapter', 'PATH env', 'CLAUDE_CONFIG_DIR', 'CODEX_HOME', 'tooling status', plus Korean variants. This matches the 'comprehensive coverage of natural terms including synonyms' anchor; level 4 ('a few natural terms missing') does not fit given both English and Korean variants and exact env-var names are present.

Distinctiveness Conflict Risk

The niche is a clear, narrowly-scoped domain (adapter parity between two named runtime files in the Stave codebase), so conflict risk with other skills is minimal. Level 4 ('minor overlap risk with closely related skills') does not apply because the description names the exact files and distinguishes itself from adjacent concerns like routing.